Device for recharging the storage batteries of automobiles.



No. 815,360. PATENTED MAR. 20, 1906.

L. LYNDON.

DEVICE FOR REGHARGING THE STORAGE BATTERIES OF AUTOMOBILES.

. APPLICATION FILED MAY 4, 1904. Bmrnwm) MAR. 23, 1905.

'] SHEETS-SHEET 1.

y 3 t: Inventor:

No. 815,360. PATENTBD MAR. 20, 1906.

L. LYNDON. DEVICE FOR REGHARGING THE STORAGE BATTERIES 0F AUTOMOBILES.

APPLICATION FILED MAY'l, 1904. RENEWED MAR. 23. 1905.

7 SHEETSSHEET 2 No. 815,360. PATENTED MAR. 20, 1906.

L.LYNDON.

DEVICE FOR REGHARGING THE SWORAGE BATTERIES 0F AUTOMOBILES.

APPLICATION FILED HAY 4, 1904. RENEWED IAB. 23, 1905.

7 SHEETS-BBB 4.

No. 815,360. PATENTBDMAR. 20, 1906. L.LYND-ON. DBVIGEPORRBGHARGINGTHBSTORAGEBATTERIESOFAUTOMOBILES. APPLICATION FILED MAY 4, 1904. RENEWED IAB. 23,1905.

' 7 SHEETS-SHEET 5.

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' I I I 3 3 T mllmlr No. 815,360. PATENTED MAR. 20, 1906.

L. LYNDON;

DEVICE FOR REOHARGING THE STORAGE-BATTERIES 0F AUTOMOBILES. urmourox FILED run, 1904. RENEWED MAR. 23, 1905.

7 SHEETS-SHEET 6 In Mentor. Witnesses:

PATEN'IED MAR. 20, 1906. L. LYNDONV DEVICE FOR REGHARGING THE Sil'ORAGE BATTERIES 0F AUTOMOBILES.

AFPIJIOATION FILED IAY4, 1904. RENEWED IAR. 23, 1905.

7 SHEETS-SHEET I.

In men tar.-

Witnesses.-

Mr I

I equipped with means UNITED STATES PATENT ()EFH 1E.

LAMAR LYNDON, OF NEW YORK, N. Y.

DEVJCE FOR RECHARGING THE STORAGE BATTERIES'OF AUTOMOBILES.

Specification of Letters Patent.

Patented March 20, 1906,

Implication filed May 4, 1904. Renewed'Ma-rch 23, 1905; Serial No. 251.596-

cles propelled by electric motors which receive their energy from storage batteries carried by the vehicles themselves much difficulty is often experienced in obtaining the electric current necessary for the recharging of the battery, particularly in view of the fact that the electric current is now commonly distributed as alternatin current, whereas direct current is required for the recharging. Transforming-stations exist; butit is not always convenient or even possible to reach such a transforming-station when the necessity for recharging arises. The installation of a spe-v cial transforming plant for an individual operator is somewhat expensive and is not always practicable. Moreover, in the case of a single-phase rotary converter, which is a satisfactory form, since there is no rotary magnetic field to cause the armature to start from a condition of rest, s ecial means must be provided for bringing tiie armature u to synchronous speed. Obviously it would be of great advantage in the operation of ever automobile to have the automobile itse f for the converting of the current, especiall if such means do not add greatly to the weight/of the vehicle or to the expense of construction thereof.

It is the object of this invention to provide such means, so that it will always be possible to recharge the batteries at any oint where it is possible to secure a supply 0 alternating current. To attainthis object, provision is made whereby the driving-motor of the electrically-propelled vehicle can be utilized as a rotary converter, the motor being, so arranged that when used for such purpose its energy shall not be expended in the propulsion of the vehicle, and suitable collecting devices, switches, and voltage-controlling means being provided whereby alternating current can be su plied from anyconvenient source and recti ed by the motor then operating as a converter and delivered to the battery, it being also possible, if desired, to provide for the bringing of the motor u to synchronous speed by current supplied rom the battery before it is attempted to recharge the battery from the source of alternating current. It will be understood that the armature may be brought u .to a speed equal to or above synchronism y any suitable means, whether by the battery itself or by hand-operated-devices. When it has been so brought up to speed, the circuit from the armature to the battery is opened and the circuit fromv the collecting-rings carried by the armature to the sources of alternating current is closed, and if the speed of rotation of the armature is then above that of synchronism it will decrease until the speed of synchronism is reached and will then continue to rotate synchronously. At such time the direct current maybe taken from the brushes of the ordinary commutator and delivered to the battery for recharging the same. During the operation of the motor as a rotary converter in this manner the drivin -wheels of the vehicle may be raised from t e ground to rotate freely or the motor ma from the driving-wheels y an convenient mechanical device. The rate 0 current-flow from the source of alternating current through the motor operating as a rectifier or converter to regulated, and since the voltage and the current-flow at the direct-current brushes of the motor are proportional to the voltage and current flow at the alternating current brushes or collector :rings such regulation may be effected in any one of the several different'ways, as by a resistance in the directcurrent circuit, a resistance in the alternating-current circuit, an ordinary transformer in the alternating-current circuit, a'chokingcoil in the alternating-current circuit, or a rheostat either in the direct or the alternating current circuit. This regulating device may be made a part of the vehicle or may be located at a fixed point at which the charging is to be effected, as may be preferred.

The invention will be described in detail and will be explained more fully hereinafter withreference to the accompanying drawings, in which Figure '1 is a view in elevation of a motorvehicle of ordinary type to which the present invention may be applied. Fig. 2 is a detail view of the motor, illustrating one formbf means for permitting the rotation of the linotor as a converter in recharging. Fig. 3 IS a the battery must of course be.

be disconnected ICC diagrammatic view of one form pulled out or replaced,

of voltagecontrolling means. Fig. 4 is a diagrammatic view illustrating the windings of the motor and the connections thereof with the points of the auxiliary controller and thence the points of the main controller. Figs. 5 to 14 are diagrammatic views representing the different connections of the motor under different conditions. Fig. 15 is a diagrammatic view representing a different winding of the motor from that represented in Fig. 4. Fig. 16 is a view generally similar to Fig. 4, but showing the movable contacts of the controllers in relation to the fixed contacts or terminals thereof. Fig. 17 is a view similar to Fig. 16, but illustrating the modification of the winding of the motorindicated in Fig. 15.

In the embodiment of the invention illustrated in the drawings so much of an automobile of ordinary type is re resented in Fig. 1 as'is necessary to enable the application of the invention to be understood. The body A of such vehicle may be arranged to receive and support the storage battery (indicated at B) in any usual or suitable manner, while the motor C is also mounted as may be preferred and is suitably connected with the driving axle or driving-wheels, the armature-shaft S in the present instance being shown as provided with a pinion P, which engages a gear X on the drive shaft or axle D. As hereinbefore suggested, it is necessary to provide means whereby when the battery is being recharged With the motor operating as a rotary converter the ener of rotation of the motor shall not be expen ed in the propulsion of the vehicle. Obviously this might be accomplished by raising the drive-wheels of the vehicle from the floor or by disconnecting the transmittingea'rin the motor an the rive-wheels. As represented in the drawings, the pinion P is secured thereon for rotation by a sliding key or feather V, which is represented as having a knob or handle by which it can be readily as may be desired. The motor isprovided with the usual commutator c, with its direct-current brushes 0' and c and is enerally constructed and arranged as usua except that the armature or armature-shaft is provided with collectingrings 0 and c, which are res ectively connected with the armature-win ings, and that there is a plurality of field-windings, which may be thrown into parallel or parallel groups to give a sufiiciently low, resistance and a sufficiently high magnetizing power to enable the machine to work satisfactorily as a series driving-motor at different speeds and into series to give a sufficiently high resistance to enablethe machine to work satisfactorily as a shunt-wound rotary converter. As shown in Fig. ,4, there may be two coils on each pole,'as d" d (2 &c., and e e e &c., the several coils d (1 &c., being of comparaat any point between tively small Wire to offer a comparatively high resistance, while the coils e e, &c., may be of coarser 'wire to have a comparatively low resistance. As shown in Figs. 4, 5, and 6, the several coils d (1 &c., are connected to the points 9 g", &c., of a group G of points of a suitable auxiliary controller, (indicated generally at G,)the coils e, e, and e to the omts v g g, &c., of a group G of points of suc auxiliary controller, and the coils e and e and e to the points g" g, &c., of a group Gr of such contacts, the auxiliary controller being provided with twenty-four points or contacts for a six-pole motorhavin two coils to each pole. The several coils 0 each group may thus be connected in series, as shown 111 Fig. 5, to have a comparatively high resistance, or in parallel, as shown in Fig. 6, to have a comparatively low resistance. Connections are also provided, as also shown in Figs. 5 and 6, from the auxiliary controller Gto the points or contacts 6, 7, 8, 9, 10, and 11 of the main controller F, whereby the several grou s may be connected in series, as shown in and 6, or two groups G nected in series, with the group G cut out, or the roups (3* and G may be connected in para lel, with the group G cut out, or the several groups may be connected in parallel.

The controller F is of ordinary construction and is sufiiciently illustrated with its connections, in Figs. 7 to 14, in which different positions are represented, the several groups of field-coils being represented by single coils to avoid unnecessary complication of the drawings. Four contacts (marked 1, 2, 3, and 4, respectively) may be provided for connection to the brushes 0 and c of the motor to afford convenience in the reversal of the motor, if desired; but in the following description these will be regarded as connected for rotation of the motor in one direction only. Contact 4 is permanently connected to contact 5. Between the contacts 5 and 5 is connected a resistance R, for a purpose to be referred to hereinafter. The contacts 6, 7, 8, 9, 10, and 11 are connected with the several groups G, G, and G of the field-coils through the auxiliary controller G, as already stated. The, contacts 12 and 13 are igs. 5 and G may be conconnected with the terminals of the battery B and with the chargin -plug through a double-throw switch 8*, as ereinafter described. The contact 14 is connected with one of the collecting or slip rings 0 and c of the motor and the contact 15 with one of the points of the switch 8*. It will be understood that each of the controllers employed is of the ordinary and well-known construction and ar rangement adapted for the purpose of shifting the connections of the motor for. rechargin the battery, or for propelling the motor at derent speeds, or for bringing the motor up to synchronous speed, and that-"they may be located at any convenient point. The contact 13, and the contact sf with the other ter-' minal'of the battery and contact 12.

When the motor is at rest, all of the fieldcoils are in arallel and all contacts of the main contro ler are open. If under these conditions it is desired to charge the battery with direct current, the'switch S is thrown to connect the terminals of the charging-plug with the terminals of the battery, as shown in Fig. 7.

' For the purpose of driving the motor propelling the carriage at its first or lowest speed the several coils of each group of fieldcoils are connected in parallel and the three groups are connected in series with the armature and the battery, as shown'in Fig. 8. Under these conditions the motor runs as a series motor with a strong field, which gives a strong starting torque, a low starting armature-current, anda slow speed, the two latter effects being due both to the strong field and to the fact that the resistance of the group made up of the higher resistance-coils cuts down the voltage at the aririature-terrmnals," acting, in fact, as a starting resistance as well as a field-winding; The controller connections'fonthe second or intermediate speed are shown in Fig. 9, in which the several coils of the grou s G and G of the fieldcoils being in paralle as before, the group G is cut out and the grou s G and G are in series. As com ared with the last-described connections, t e speed of the motor is increased because of the weakened field and the re :luced resistance in circuit. For the third or fastest s eed the connections are shown in Fig. 10. he coils of groups G and G being connected in parallel, the two groups ,are'

themselves connected in parallel and group G is cut out.

In Fig. 11 are shown the connections which permit the motor to be used as an electric brake. The several groups of field-coils are connected in series with the armature and the battery; but the connections between the field-coils and the battery are reversed, so as to, send current throu h the coils in a direction opposite to that in icated in Fig. 8. 4

' In preparing for the use of a motor as a rotary converter after the wheels of the vehicle have been lifted from the ound or the driving mechanism has been dlsconnected it is necessary to bri the motor up toor above the speed of sync oni'sm. Obviously this can be effected by any convenient meanssuch, for example, as a hand-operated ear; but the battery itself may be employe for the purpose. I pose (represented in Fig. 12) are as follows: All the coils of the several groups of field-coils The connections for this purbeing connected in series, the groups themselves are connected in series with each other and with the resistance R (to further decrease the field-current) in shunt with the armature.

Under these conditions the motor rotates,

running as a shunt-motor without load, and quickl attains a hi h velocity. When the desire velocity has een attained, the alternating-current main being plu ged in at H, the-switchS is shifted to esta lish connectionfrom s to s and from s to s, and the controller F is further shifted to open the armature-circuit to cut out the resistance R and to make connection from 14 to 15, as shown in Fi 13. This throws alternatin current on t e collecting-rings c and c, and

the motor falls into step, runnin in synchronism and with strong external fieFd excitation. A further shifting of thecontroller F closes the armature-circuit, and the otherconnections remaining as before alternating current flows into the armature through the collecting-rings c and c and is delivered to be rectified or converted, a portion being then passed 'through the field-coils in the proper direction-that is, in the samedirectlon as that in 'whichthe current flows through the fields when the motor is operating to propel the vehicleand a portion going tofthe battery, which is rechar ed thereby. The delivery of current to the attery may be varied by a suitable rheostat, (indicated at R which may be located at any convenient point, as between the switch and the battery, or by an ordinary choking-coil K, which may likewise be located at any convenient point, either on the vehicle or at the charging-station, or by both of such devices. The usual step-down transformer T, as shown in Fig-1, ma be employed to so regulate the voltage 0 the enterin current that the desired voltage .at

.the col ecting-rin s may be attained, or an autotransformer such as that shown in Fig. 3, may be employed for the purpose, such autotransformer comprising an iron IIO core t, which is wound with a number of turns of wire of the required size, the terminals of the winding being connected to the alternating-current mains, respectively. The connections to the controller are taken off at. an intermediate point as to one of them, and the ratio of the voltage in the mains on opposite sides of this autotransformer will be equal to the ratio between the number of turns respectively included. -In each case, therefore, the connections to the transformer will be so made as to 'eld the desired voltage in the current supp ed.

It is understood that one or more of the several regulating devices may be employed in each instance, as most convenient.

When the apparatus commences operation as a converter, it is possible that the polarity at the direct-current brushes 0 and 0 may be reversed. This will be indicated at the voltmeter, and thereupon the connections through contacts 1, 2, 3', and 4 of the controller F should be shifted so that the connections shall be from the positive pole of the machine to the positive pole of the battery.

In order to avoid confusion, the movable contacts of the controllers F and G have not been referred to heretofore, nor are they shown in Fig. 4 of the drawings. In Fig. 16, however, the movable contacts of the main controller are indicated generally at F, and the movable contacts of the auxiliary controller are similarly represented at G The arrangement of the movable contacts of each of these controllers will be readily understood upon reference to Fig. 16 and need not be described in detail herein. It will be suflicient to state that when the first and third rows of contacts of the movable portion of the auxiliary controller are over the corresponding sets of'fixed contacts all of the six shunt-coils of the motor are in parallel on the lower row, and the series coils are grouped into two sets of three coils each, the coils in each set being in parallel, and when the second and fourth rows of the contacts of the movable portion are over the corresponding rows of fixed contacts the coils are connected in series. When the open space on the moving portion of the main controller is over the row of fixed contacts thereof, the battery-circuit and the motor-circuit are open and the vehicle is at rest. A forward movement of the controller from its initial position gives successively the lowest speed, the intermediate speed, and the highest speed. A reverse movement of the controller from its initial position gives first the brakin efiect, then a speed abovesynchronism, t en synchronous speed, and finally the operation of the motor as a rotary converter while charging the battery from a source of alternating current.

A series motor or dynamo-electric machine has been particularly referred to thus far, since a motor of this type is generall used for the propulsion of vehicles; but itwill be obvious t at the improvement is equally applicable to a shunt or compound-wound motor, the shunt-coils receiving current from either the battery or the commutator. Such an arrangement is represented in Figs. 15 and 17, in which the shunt-field is shown at SF and the several groups of series fieldwindings at S, S, and S A detailed description of this arrangement will be unnec- .essary in view of the particular description of the arrangement first referred to, and it will be understood that for the first speed of the motor the group S, S and S are in series.

For the next speed the group S and S are in series, with the group S cut out. For the third speed the group S and S are in parallel, and for the fourth speed th group S, S and S may be cut out altogether, the shunt-field of course remaining in circuit in each instance. When the machine is operating as a rotary converter, the connections are the same as for the first motor-speed just referred to. The shunt-field magnetization is low enough to bring the speed up to or above synchronism, and as the group S comprises numerous turns its effect, together with that of the group S and 8, gives a strong magnetization with passage of current to the battery. The relation between the contacts of'the moving portion of the main and auxiliary controllers to the fixed contacts of such controllers in this embodiment of the invention will be readily understood upon examination of Fig. 17 without detailed explanation herein.

Other modifications of the general features of the device will suggest themselves to those skilled in the art, and it is to be understood that the invention is not restricted to the particular arrangements shown and described herein.

I claim as my invention- 1. In an electrically-propelled motor roadvehicle, the combination of a dynamoclectrical machine mounted' on the vehicle and having a commutator and independent collecting devices, a storage battery adapted to furnish the total propelling-current also mounted on the vehicle, and connections whereby at will current may be supplied from said battery to said machine to operate the same, or alternating current may be delivered to said machine through said currentcollecting devices when the vehicle is at rest and being there rectified and changedto-direct current at the commutator be supplied from said machine to the battery to recharge the same, substantially as shown and described.

2. In an electrically-propelled motor roadvehicle, the combination of a dynamo-electrical machine mounted on the vehicle and having a commutator, and independent current collecting devices, a storage battery adapted to furnish the total propelling-current also mounted on the vehicle, and connections whereby at will current may be supplied from said battery to said machine to operate the same for propelling the vehicle, or from said battery to said machine to operate the same without load, or alternating current may be sup lied to said machine through said current-col ecting devices when the vehicle is at rest and being there rectified and changed to direct current at the commutator be supplied, from said machine to the battery to recharge the same, substantially as shown and described.

ICC

3. In an electrically-propelled vehicle, the

commutator be sup lied from said machine to the battery to rec arge the same,,substantially as shown and described.

4. In an electrically-propelled motorroadvehicle, the combination of a dynamo-electrical machine mounted on the vehicle and having a commutator and independent currentcollecting devices, astorage battery adapted to furnishthe total propelling-current also mounted on the vehicle, connections whereby at will current may be supplied from said battery to said machine to operate the same, or alternating current may be delivered to said machine through said current-collecting devices when the vehicle is at rest and being there rectified and changed to direct current at the commutator be supplied from said charge the same, and a resistance includedin the circuit to regulate the current delivered to the battery, substantially as shown and described.

5. In an electrically-propelled vehicle, the combination of a dynamo-electric machine mounted on the vehicle and having a commutator and current-collecting devices, driving connections between the same and'the drive-wheels of the vehicle, means to disconnect said driving connections, a storage battery also mounted on the vehicle,- connections whereby at will current may be supplied from said battery to said machine to o erate the same, or alternatin current may e delivered to said-machine, tl irough said ourrent-collecting devices and being there rectified and changed to direct current at the commutator be supplied from said machine to the battery to recharge the same, and a resistance included in the circuit to regulate the current delivered to the battery, substantially as shown and described.

6. In an electrically-pro elled motor roadvehicle, the combinationo adynamo-electric machine mounted on the vehicle, and having a commutator and independent current-collecting devices, a storage battery adapted to furnish the total ropelling-current also mounted on the vehic e, connections whereby at will current ma be an plied from said battery to said mac 'ne to 'perate the same,

or alternating current may be delivered tosaid machine through said current-collecting vehicle, machine to the battery to redevices When-the vehicle is at rest and being there rectified and changed to direct current at the commutator be sup lied from said machine to the battery to recl arge the same, and a step-down transformer included in the alternatingcurrent circuit to regulateithe voltage of the current delivered to the apparatus, substantially as shown and described.

7. In an electrically-propelled vehicle, the combination of a dynamo-electric machine mounted on the vehicle and having a commutator and current-collecting devices, driving connections between the same and the drive-wheels of the vehicle, means to disconnect said driving connections, a storage battery also-mounted on the vehicle, connections'whereby at will current may be supplied from said battery to said machine to operate the same, or alternating current may be delivered to said machine through said current-collecting devices. and being there rectified and changed to direct current at the commutator be supplied from said machine, to the battery to recharge the same, and a step-down transformer included in the alternating-current circuit to regulate the voltage of the current delivered to the apparatus,

substantially as shown and describe 8. In an electrically-propelled motor roadthe combination of a dynamo-electric'machine mounted on the vehicle and having a commutator and independent current-collecting devices, a storage battery adapted to furnish the total propelling-current also mounted on the vehicle, connections whereby at will current may be supplied from said battery to said machine to operate the same, or alternating current may delivered to said machine through said current-collecting devices when the vehicle is at rest and being the e rectified and changed to direct current a the commutator be supplied from said machine to the battery to recharge the same, and astep-down transformer included in the, alternating-current circuit to regulate the voltage of the current delivered to the apparatus, said transformer comprising an'iron core and a winding thereon, said winding being connected at its terminals with the supp y-mains and at intermediate points with the delivery-mains, substantially as shown and described.

'9. In an electrically-propelled motor roadand beingthere rectified and changedto diattery to said motor to 08- root current at the commutator be supplied from said motor to the battery to recharge the same, substantially as shown and described.

10. In an electricallypropelled motor road-vehicle, the combination of a series motor mounted on the vehicle and having a commutator, and independent current-collectin devices, a stora e battery adapted to furnisl i the total propelling-current also mounted on the vehicle, and connections whereby at will current may be supplied from said battery to said motor to operate the same for propel ing the vehicle, or from said battery to said motor to operate the same without load, or alternatin current may be supplied to said motor t ou h said current-collectin devices when t e vehicle is at rest and eing thereby rectified and chan ed to direct current at the commutator e supplied from said motor to the battery to recharge the same, substantially as shown and described.

11. In an electrically-propelled vehicle, the combination of a series motor mounted on the vehicle and having a commutator and current-collecting devlces, driving connections between the same and the drive-wheels of the vehicle, means to disconnect said driving connections, a storage battery also mounted on 'the vehicle, and connections whereby at will current may be supplied from said battery to said motor to o erate the same, or alternating current may e delivered to said motor through said currentcollecting devices and being there rectified and changed to direct current at the commutator be supplied from said motor to the battery to recharge the same, substantially as shown and described.

12. In an electrically-propelled motor road-vehicle, the combination of a series motor mounted on the vehicle and having a commutator and independent current collectin devices, a storage battery adapted to furnis the total propelling current also mounted on the vehicle, connections whereby at will current may be supplied from said battery to said motor to operate the same, or alternating current may be delivered to said motor throu h said current-collectin devices when tl ie vehicle is at rest and ing there rectified and chan ed to direct current at the commutator, supp ied from said motor to the battery to recharge the same, and a resistance included in the circuit to regulate the current delivered to the battery, substantially as shown and described.

13. In an electrically propelled motor road-vehicle, the combination of a series motor mounted on the vehicle and havin a commutator and inde endent current-co lectin devices, a storage attery adapted to furnis the total ropelling-current also mounted on the vehic e, connections whereby at will ourrent may be supplied from said battery to said motor to operate the same, or alternating current may be delivered to said-motor through said current-collecting devices when the vehicle is at rest and being there rectified and changed to direct current at the commutator be supplied from said motor to the battery to recharge the same, and a stepdown transformer included in the alternatingcurrent circuit to regulate the voltage of the current delivered to the a paratus, substantially as shown and descri ed.

14. In an electrically-propelled vehicle, the combination with a dynamo-electrical machine mounted on the vehicle and having a commutator and independent current-collecting devices and a p urality of groups of field-coils, a storage battery also mounted on the vehicle, and connections whereby said groups of field-coils may be thrown into parallel to give a low resistance and high magnetizing power for operation of the machine as a Sel'leS driving-motor, or into series to give a high resistance to enable the machine to o crate as' a shunt-W0 and rotary converter, subtantially as described.

15. In an electrically-propelled vehicle, the combination with a dynamo-electrical machinemounted onthe vehicle and having a commutator and independent current-collecting devices and a plurality of groups of field-windin s, a storage battery also mounted on the ve icle,- an auxiliary controller and connections whereby'the several coils of each of said roups of field-coils may be connected -1I1 ara lel or in series, and a main controller an connections from said auxiliary controller whereby the relations of the groups of field-coils to each other and to said other de vices may be changed, substantially as described.

16. In an electrically-propelled vehicle, the.

combination with a dynamo-electrical machine mounted on the vehicle and having commutator and independent current controlling devices and a plurality of groups of field-coils, a storage battery also mounted on the vehicle, connections whereby said rou s of field-coils may be thrown into para lel or operation of the machine as a'serles drivingmotor or into series for operation of the machine as a'shun'twound rotary converter, 21 charging-plug, and a switch and connections whereby alternating current may be delivered to the machine when operat' as a shunt-wound rotary converter, substantially as described.

This specification si ed and witnessed this 28th day of April, D. 1904.

LAMAR LYNDON. 

